The following US patents and patent publication are incorporated herein by reference.
U.S. Pat. No. 8,075,304 discloses a power burner system for use with a heating appliance. The power burner system includes a burner tube, a gas valve for providing gas to the burner tube, and a variable-speed combustion air blower for mixing air with the gas provided to the burner tube. The burner system further includes a controller in communication with the gas valve and the combustion air blower. The controller may also be in communication with various other devices of an appliance, such as a variable-speed air-circulating fan, a variable-speed exhaust fan, or various sensors associated with the heating appliance. The controller modulates the gas valve and the combustion air blower to maintain substantially stoichiometric conditions of the gas and air provided to the burner tube and as a function of signals from at least one of the devices. In one embodiment, the burner system may be used in a conveyor oven.
U.S. Patent Application Publication No. 2016/0047547 discloses a water heating device, comprising a burner and a flame current measuring device for measuring a flame current. The measuring device comprises two electrodes and a voltage source. Each of the poles of the voltage source is connected to one of the electrodes. The water heating device further comprises a heat exchanger which is electrically insulated relative to the burner. The burner and the heat exchanger form the electrodes of the flame current measuring device. The heat exchanger functioning as electrode can be earthed. The measured flame current can be used to determine the excess air factor of the combustion. The water heating device can further comprise an air/fuel controller for controlling the air/fuel ratio, wherein the air/fuel controller uses the determined excess air factor to control the air/fuel ratio.
U.S. Pat. No. 5,984,664 discloses an apparatus that provides an air/fuel mixture to a fully premixed burner and a fuel line that provides fuel to the burner. A fan supplies air at a variable flow rate to the fuel to form the mixture. A sensor senses aeration of the fuel combustion products. A controller controls the air flow rate in dependence upon the aeration sensed and in such a way that the air flow rate is sufficient to maintain the aeration at or close to a predetermined value. The controller maintains the air flow rate at one of a number of differing predetermined values which are in the form of a geometric series characterized by a constant value of the ratio between successive values.
U.S. Pat. No. 4,712,996 discloses a gas burner control system for controlling operation of a furnace. A blower is fluidically connected to the combustion chamber of the furnace. The system utilizes a mass flow sensor for preventing or discontinuing burner operation in the event of a blower failure or a predetermined degree of blockage in the fluid flow path controlled by the blower. The mass flow sensor includes a circuit which enables use of unmatched sensors, enables establishing of a desired value of temperature difference between sensors, enables establishing a temperature difference that is not constant so as to compensate for different ambient air densities, and enables compensating for voltage variations at different ambient air temperatures.